The present invention relates to the field of assistive devices for disabled people, and in particular to devices that enable the user thereof to selectively apply a pneumatic signal to multiple assistive technology appliances.
According to the latest reports from the National Center for Health Statistics, 13.6 million Americans have limited use of their hands and 7.4 million Americans use assistive technology devices to accommodate mobility impairments. For severe cases of mobility impairments such as quadriplegia and cerebral palsy a sip-and-puff system provides a reliable mechanism for controlling assistive technology devices. The sip-and-puff system uses a breathing tube to produce one or more switching signals. For example, a system that differentiates soft sip, soft puff, hard sip, and hard puff can produce four switching signals, which are sufficient for controlling sophisticated devices such as a powered wheelchair.
A problem arises when a person uses more than one assistive technology device and each device has its own sip-and-puff control. Multiple sip-and-puff tubes are difficult to position and result in congestion in front of the user""s face. Prior art has addressed this problem to a certain extent by use of four separate inline tubes attached to and supported by a single arm (Quad Puff System or Quad Sip System, Enabling Devices, www.enablingdevices.com). However, a person who has limited head and neck mobility may have difficulty reaching all four tubes. The congestion problem still remains because the multiple inline tubes block a significant portion of the person""s view.
U.S. Pat. No. 5,600,311 describes an environmental control system for the severely disabled that has an auxiliary pass-though port. A single switch controls the environmental control system by use of the sequential scanning method described above. When the auxiliary pass-though port is selected, the system suspends the scanning and enters the pass-through mode. In the pass-though mode the input switch closures are passed to the target device connected to the auxiliary port. The pass-though mode is exited by a long depression of the switch for a preprogrammed time period. However, this pass-through method is only for an electrically-controlled switch. It does not solve the problem of controlling a device that requires a plurality of different actions from a sip-and-puff tube. The long depression of the switch as the exit signal may also impose a limitation on operating a device that requires closings the switch for long periods of time.
The present invention addresses the aforementioned drawbacks.
Broadly, the invention comprises an apparatus for controlling a plurality of assistive technology devices that includes a manifold comprising a pneumatic input port, a first pneumatic output adapted to communicate with a first assistive technology device and a second pneumatic output adapted to communicate with a second assistive technology device. The first pneumatic output is in communication with a first solenoid valve operative to close and open the first pneumatic output port. The second pneumatic output port is in communication with a second solenoid valve operative to close and open the second pneumatic output port.
Means for controlling the opening of either the first or second solenoid valve are actuated by the passage of a pneumatic signal through said input port. When the first pneumatic valve is opened the input port and the first output port are in communication, the second pneumatic valve being closed, to create a first pneumatic flowpath from the input port to the first output port to allow the input port to communicate with the first assistive technology device. When the second pneumatic valve is open the input port and the second output port are in communication, said first pneumatic valve being closed, to create second pneumatic flow path to allow the input port to communicate with the second assistive technology device. Means for determining when the application of the pneumatic signal will actuate the means for controlling to open either said first solenoid valve or said second solenoid valve.
In another aspect, the invention includes a pneumatic demultiplexer that allows a person with a disability to control multiple assistive technology devices by the use of a single sip-and-puff tube. The devices to be controlled are operated by a single pneumatic or electrical switch input. The pneumatic demultiplexer is under the control of a microprocessor. In a scan stage the user selects the target device via scrolling LED indicators. When a specific device is chosen, a corresponding solenoid valve is activated to connect the input sip-and-puff port to the pneumatic output port. In the activation stage, the input sip-and-puff tube controls the target device directly via the pneumatic demultiplexer. The microprocessor monitors the line activity via a sip-or-puff switch. A timer is implemented by the microprocessor. After there is a lack of activity for a pre-programmed time period, the system switches from the activation stage back to the scan stage.
In yet another aspect, the invention includes a pneumatic demultiplexer that allows the use of a single sip-and-puff tube to control a plurality of devices that are operated by electrical and/or pneumatic switches.
These and other objects, features and advantages of the present invention will become more apparent in light of the following detailed description of the preferred embodiments thereof, as illustrated in the accompanying drawings.